The present invention relates to the field of the cutting of blocks of stone and more particularly to a wedge intended to be inserted in a cutting slot when horizontally cutting a block of stone.
When a block of stone is being cut horizontally, it is absolutely essential that wedges be inserted in the cutting slot so that the upper part of the block of stone does not impede the progression of the cutting wire.
When there is a desire to automate the horizontal cutting of blocks of stone, it is appropriate to produce an automatic device which controls the progress of the cutting wire and an automatic device (possibly the same one) which manages the insertion of the wedges in the cutting slot.
Now, it has been found that as cutting progresses, the cutting wire becomes worn and its thickness reduces by a few tenths of a millimeter.
It therefore follows that the cutting slot does not have the same thickness when the cutting wire is worn as it does when this wire is new and that the wedges have therefore to have different thicknesses according to the state of wear of the cutting wire so as always to be inserted correctly in the cutting slot.
In order to automate the insertion of wedges of different thicknesses into the cutting slot, one solution consists in having, in the store of the automatic device, wedges of thicknesses that vary according to the thickness of the cutting wire, but this makes managing the automation enormously complicated.
The present invention intends to overcome the drawbacks of the prior art by providing a wedge whose overall thickness can vary between a maximum thickness value and a minimum thickness value.
To do this, the wedge according to the invention is made in two parts, the two parts having means allowing them to slide one upon the other so that the double wedge has the ideal thickness.
Advantageously, the maximum thickness of the double wedge according to the invention corresponds to the thickness of a new cutting wire and the minimum thickness of the double wedge corresponds to the thickness of said cutting wire when it is worn, so that the wedges can always be inserted perfectly into the cutting slot.
Advantageously also, the means which allow the parts to slide one upon the other allow, automatic adjustment of the thickness of the double wedge, by virtue of the forces available upon insertion.
Thus, automating the insertion of the wedges into the cutting slot requires just one single type of wedges and does not entail operations of sorting the wedges before placing them in the store of the insertion device.
According to a few advantageous features of the invention:
said means consist of two complementing slopes formed respectively on the parts without exerting any parting force and. without exerting any pressure in the cutting slot;
said means are in the form of two complementing dovetails;
the part has lateral edges which, at least partially, in section, have the shape of a V, guaranteeing that the wedge can be picked up and engaged in the cutting slot.
Another object of the present invention relates to a method for horizontally cutting a block of stone placed on a fixed frame using a cutting wire, which is unique, mounted on cutting means that can move horizontally and vertically on the frame, of the type comprising a step in which wedges are inserted into the cutting slot by insertion means, characterized in that said wedges are in accordance with any one of the aforementioned characteristics.
According to an advantageous characteristic, said wedges are inserted regularly during a temporary halt in the progression A of the cutting means.
According to another advantageous characteristic, during the wedge-insertion operation, two wedges are inserted simultaneously into the cutting slot, one wedge being inserted respectively from each side of said block of stone by the insertion means.
Another object of the present invention relates to a device for horizontally cutting a block of stone placed on a fixed frame of the type comprising a cutting wire, which is unique, mounted on cutting means that can move horizontally and vertically on the frame, the cutting means being made up of at least one drive flywheel rotated by a motor and a return flywheel, the flywheels having the task of rotating R the cutting wire and means for inserting wedges into the cutting slot, each comprising at least one wedge store, the cutting means and the insertion means are secured together and arranged so they can move vertically on a vertical support capable of moving horizontally with respect to the frame, characterized in that said wedges are in accordance with any one of the aforementioned characteristics.
According to a few advantageous features of the device according to the invention:
the means of inserting said wedges each comprise an arm which can move with respect to the store, at the end of which is positioned a mobile picking finger tasked with picking up the wedges;
the arm further comprises, at its end, a wedge-tensioning ram allowing said wedge to be tailored to the size of the slot;
the store is made up of a wedge box that can move vertically on a vertical slideway and a fixed bottom stop.
The invention will be better understood with the aid of the description given hereinafter of one embodiment thereof which is given by way of nonlimiting example with reference to the appended FIGURES.